ac94809b64
* Remove use of deprecated ioutil functions from examples * Remove usage of ioutil from gobyexample's own scripts + regenerate output
66 lines
1.8 KiB
Go
66 lines
1.8 KiB
Go
// Throughout program execution, we often want to create
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// data that isn't needed after the program exits.
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// *Temporary files and directories* are useful for this
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// purpose since they don't pollute the file system over
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// time.
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package main
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import (
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"fmt"
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"os"
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"path/filepath"
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)
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func check(e error) {
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if e != nil {
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panic(e)
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}
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}
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func main() {
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// The easiest way to create a temporary file is by
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// calling `os.CreateTemp`. It creates a file *and*
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// opens it for reading and writing. We provide `""`
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// as the first argument, so `os.CreateTemp` will
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// create the file in the default location for our OS.
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f, err := os.CreateTemp("", "sample")
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check(err)
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// Display the name of the temporary file. On
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// Unix-based OSes the directory will likely be `/tmp`.
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// The file name starts with the prefix given as the
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// second argument to `os.CreateTemp` and the rest
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// is chosen automatically to ensure that concurrent
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// calls will always create different file names.
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fmt.Println("Temp file name:", f.Name())
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// Clean up the file after we're done. The OS is
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// likely to clean up temporary files by itself after
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// some time, but it's good practice to do this
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// explicitly.
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defer os.Remove(f.Name())
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// We can write some data to the file.
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_, err = f.Write([]byte{1, 2, 3, 4})
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check(err)
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// If we intend to write many temporary files, we may
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// prefer to create a temporary *directory*.
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// `os.MkdirTemp`'s arguments are the same as
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// `CreateTemp`'s, but it returns a directory *name*
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// rather than an open file.
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dname, err := os.MkdirTemp("", "sampledir")
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check(err)
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fmt.Println("Temp dir name:", dname)
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defer os.RemoveAll(dname)
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// Now we can synthesize temporary file names by
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// prefixing them with our temporary directory.
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fname := filepath.Join(dname, "file1")
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err = os.WriteFile(fname, []byte{1, 2}, 0666)
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check(err)
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}
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